Unusual nucleic acid binding properties of factor 2, an RNA polymerase II transcript release factor.
Drosophila factor 2, an RNA polymerase II transcript release factor, exhibits a DNA-dependent ATPase activity (Xie, Z., and Price D. H. (1997) J. Biol. Chem. 272, 31902-31907). We examined the nucleic acid requirement and found that only double-stranded DNA (dsDNA) effectively activated the ATPase. Single-stranded DNA (ssDNA) not only failed to activate the ATPase, but suppressed the dsDNA-dependent ATPase. Gel mobility shift assays showed that factor 2 formed stable complexes with dsDNA or ssDNA in the absence of ATP. However, in the presence of ATP, the interaction of factor 2 with dsDNA was destabilized, while the ssDNA-factor 2 complexes were not affected. The interaction of factor 2 with dsDNA was sensitive to increasing salt concentrations and was competed by ssDNA. In both cases, loss of binding of factor 2 to dsDNA was mirrored by a decrease in ATPase and transcript release activity, suggesting that the interaction of factor 2 with dsDNA is important in coupling the ATPase with the transcript release activity. Although the properties of factor 2 suggested that it might have helicase activity, we were unable to detect any DNA unwinding activity associated with factor 2.
Xie
Z
Z
Department of Biochemistry, University of Iowa, Iowa City, Iowa 52242, USA.
Price
D H
DH
D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D004265:DNA Helicases / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics
D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D004247:DNA; D000251:Adenosine Triphosphatases; C109658:RNA polymerase II transcript release factor 2; D004265:DNA Helicases